Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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Gabon covers an area of some 270,000...2, straddling the Equator on the west coast of Africa. Partly dissected plateaux in the interior, rising to some 6001,000 m above sea level, give way to a fairly narrow co...

The combined coastline of Gabon, Congo, Cabinda (a separate province of...1985...). It forms the oceanic boundary of two Mesozoic and Tertiary sedimentary basins, those of Gabon and the Congo, which are separated...

In a 2-month workover campaign off the coast of Gabon, West Africa, Elf Gabon serviced 41 wells off 14 platforms, using coiled tubing to convey workover fluids pumped from a dynamically positioned ship. Use of the dynamically positioned vessel, in place of a barge that requires towing to the wellsite and anchorage in place by mooring lines, helped reduce workover cost per well by 37%. Most of the savings resulted from fewer days required for each well because the service ship travelled on its own power and pumped various workover fluids from its decks. A supply ship shuttled replacement materials from shore to platform during the campaign. A production increase of 6,177 b/d resulted from the workover, with a payout time of 80 days.

This paper reports on Gabon's largest oil field, Rabi Kounga, and a flurry of smaller reservoirs which have boosted production to 300,000 bopd. Regional geology is so complex that it generates a large discovery only once every twenty years, and operators come and go due to low discovery ratios, following market ups and downs. A hard core four remain: Elf first, Shell, British Gas, which bought Tenneco, and Amoco. Shell's Rabi Kounga discovery, which stretches from shore to shelf, boosted exploration and renewed interest for onshore licenses. The low discovery rate, however, reflects the complexity of Gabonese basins.

The Rabi-Kounga field recently discovered by Shell onshore Gabon is located at 2/sup 0/S lat. in an area of central Africa covered by dense, uninhabited, primary rain forest, 140 km south of Port Gentil, the country's economic capital. The field lies mostly within the Sette Cama Block where Shell Gabon is operator on behalf of an association in which the partners are Shell, Gabon, Elf Gabon, and SNEA. As presently defined, the Rabi-Kounga field is 12 km long and 3-4 km wide, extending northward into the Dianongo Block operated by Elf Gabon for the same association. With an expectation of 1,300 million bbl(STOIP), it appears to be the largest oil accumulation discovered in Gabon. The hydrocarbons of the Rabi-Kounga accumulation are contained within the reservoir sands of the Gamba and Dentale Formations, which form part of a rift basin of Early Cretaceous age, the Dianongo basin. The cap rocks are late Aptian evaporitic deposits (Ezanga Formation). The salt deposits and their thin underlying clastics (Gamba Formation), which unconformably overlie the continental Dentale sequence, bear evidence of the first marine influence and reflect the phase of continental separation between Africa and South America. Post-salt sediments are fully marine, corresponding to a phase of sedimentary progradation. They are represented by carbonates and clastics that were deposited on a subsiding continental margin.

Fatal Chimpanzee Attack in Loango National Park, Gabon Christophe Boesch & Josephine Head & Nikki a fatal attack on an adult male chimpanzee at a new research site in Loango National Park, Gabon. We found or habituation. Keywords chimpanzees . fatal attack . gabon . intergroup conflict Introduction Chimpanzee social

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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In some populations, chimpanzees engage in lethal aggression within and between social units. We report a fatal attack on an adult male chimpanzee at a new research site in Loango National Park, Gabon. We found a...

This article examines the practice of public relations in private sector companies in Gabon. Face-to-face, semi-structured interviews were conducted with the public relations practitioners employed in 15 companies chosen from the register of the companies at the Trade Ministry of Gabon. The interviews explored themes such as position of communication departments and communication practitioners in an organisation use of research, communication practitioners relationship with top management, gender and education of practitioners, effect of globalisation on communication practice in Gabon as well as the description of typical activities of communication practitioners. The study revealed the public relations is a developing profession in Gabon and that public relations practice in the surveyed companies displays attributes common to PR in other countries as well as some distinctive qualities shaped by the context of Gabonese history, society and culture.

Observations were made in the field and laboratory to determine the strain characteristics ofSchistosoma intercalatum in south-east Gabon. For an isolate from Franceville, data...S. intercalatum as known from sou...

Complex tool sets for honey extraction among chimpanzees in Loango National Park, Gabon Christophe. However, new observations on complex tool use by the chimpanzees of Loango National Park, Gabon, expand

To investigate West Nile virus (WNV) circulation in rural populations in Gabon, we undertook a large serological survey focusing ... findings strongly suggest that WNV is widespread in Gabon. The difference in WN...

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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This paper reports on the first U.S. tanker converted to a floating production, storage, and offloading (FPSO) unit which takes up station in Gombe-Beta field off Gabon by Dec. 1. FPSO Ocean Producer will work under a 3 year, day rate contract let late in 1990 by Amoco-Gabon Bombe Marin co., a unit of Amoco Production Co. (OGJ, Dec. 24, 1990, p. 27). Gombe-Beta field is in the Atlantic Ocean about 70 miles south of Port Gentil, Gabon. Ocean Producer will be moored in 50 ft of water 3.7 miles off Gabon, with Bombe-Beta's unmanned production platform about 820 ft astern. The vessel will be held in position by a disconnectable, asymmetric, six point, spread mooring system, It is owned and operated by Oceaneering International Services Ltd. (OISL). Affiliate Oceaneering Production Systems (OPS) converted the 78,061 dwt oil tanker MT Baltimore Sea at a capital cost of $25 million at Gulf Copper Manufacturing Corp.'s Port Arthur, Tex., shipyard. Both companies are units of Oceaneering International Inc., Houston. OPS the Ocean Producer's use in Gombe-Beta field is the shallowest water FPSO application in the world. Amoco-Gabon chose an FPSO production system for Gombe-Beta because it expects the remote field to have a short economic life, and the oil requires extensive processing.

A biodiversity analysis of the vegetation in the Forêt des Abeilles (Gabon) has been undertaken using the transects method...Paraberlinia bifoliolata (Caesalpinioideae) and Aucoumea klaineana (Burseraceae). Mean ...

Gabon-Supporting Low Carbon Development and Climate Resilient Strategies in Gabon-Supporting Low Carbon Development and Climate Resilient Strategies in Africa Jump to: navigation, search Name Gabon-Supporting Low Carbon Development and Climate Resilient Strategies in Africa Agency/Company /Organization France Agency of Development (AFD) Partner ADETEF Sector Climate Focus Area People and Policy Topics Low emission development planning, Policies/deployment programs Website http://www.afd.fr/home Program Start 2013 Program End 2015 Country Gabon Middle Africa References Low Emissions Development Strategies [1] This project focuses on four Sub-Saharan African countries and seeks to make different achievements in climate change national policies within each of those countries. This is a technical assistance program focusing on

The prevalence of cytochrome b point mutations possibly conferring atovaquone resistance in Plasmodium falciparum...isolates in atovaquone treatment-naïve patient cohorts from Lambaréné, Gabon and from South West...

Hepatitis C virus (HCV) infection is a major global public health problem in both developed and developing countries. The prevalence and genetic diversity of HCV in pregnant women in Gabon, central Africa, is not...

In 1913 Albert Schweitzer founded one of the first modern hospitals in Africa dedicated to the health of the local population. The Albert Schweitzer Hospital is located in Lambaréné, a small town in Gabon. In 198...

LedFM and conventional fluorescence microscopy (uvFM) were compared to LM in 210 samples from patients with history of fever in the last 24 hours admitted to the Albert Schweitzer Hospital in Lambaréné, Gabon.

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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A 17-month study was made of the primates using a 9-ha island of forest, surrounded by savanna, in the northern part of the Lopé Reserve, Gabon. One group ofCercopithecus cephus (plus a young maleCercopithecus ...

The article analyses activities carried out over the past 15 years to contain deforestation and to phase in sustainable forestry in three West African countries:Côte dIvoire, Cameroon and Gabon. The article firs...

...We report our recent findings on the use of tool sets by chimpanzees in Moukalaba-Doudou National Park, Gabon. Direct observations and evidences left by chimpanzees...Meliponula...sp.), which may correspond to...

The exploration potential of the Port Gentil region, characterized by some of the earliest petroleum discoveries in Gabon, continues to be of important interest today. Available seismic data are of an older vintage (1974--82), recorded with low common mid-point (CMP) fold. They are critically void of coverage through the transition zone. The geology is highly complex, characterized by salt structures and strong tectonic activity. An intensive joint exploration and reservoir definition campaign is crucial to full evaluation of this area. This article describes the 3D survey conducted during 1992 and early 1993 over a mature oil field in an around Port Gentil and incorporating elements of land, transition zone, and shallow marine data acquisition -- the 3D Mandji program.

The Ozouri Group in Gabon is comprised of finely textured siliceous dolomitic and calcareous claystones, shales, limestones, dolomites, porcellanite and cherts. It was deposited during the Late Paleocene and Early Eocene on a transgressive continental margin. It is highly siliceous and organically rich, with affinities to the Miocene Monterey Formation of California. It is often fractured by deeper structural movement of the underlying Ezanga salt. Economic oil production from the Ozouri is dependent on the most effective combination of matrix (storage) and fracture (deliverability) porosity. The most efficient combination can be related to variations in the lithologic and petrophysical characteristics of the formation. Horizontal drilling techniques can be utilized to fully exploit production from the Ozouri Group.

, of similar interactions between farming practices and the biological traits of the crops in their areas-level studies of traditional manioc farming systems in Gabon, central Africa. Combining ethnobotanical their own folk ecological knowledge of the crop. The patterns of folk reasoning with respect

We undertook a prospective study of schoolchildren aged 5-16 in an area endemic for schistosomiasis near Lambaréné in Gabon. 425 children were recruited and demographic data...P. falciparum malaria infection (thi...

To test the hypothesis that primate populations are limited by food resources, we studied the feeding ecology of three cercopithecines and one colobine in a rain forest in central Gabon. Simultaneously, we monito...

In-situ isotopic analyses of Pb and U in the highly altered zircons found in the clay and black shale layers above the Bangombé natural reactor, Republic of Gabon, were analyzed using a sensitive high resolution....

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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In this paper we describe bed (nest) and bed-site reuse by western lowland gorillas (Gorilla g. gorilla...) in Moukalaba-Doudou National Park, south-eastern Gabon. During an eight-month study 44 bed...

Using a sedimentation method, the prevalence of the nodular worm Oesophagostomum stephanostomum...(Nematoda: Strongylida) in western lowland gorillas at Moukalaba-Doudou National Park (MDNP), Gabon, was determine...

Aim of the study As part of a project to identify new compounds active on malarial parasites, we tested the in vitro antiplasmodial activity of nine plants traditionally used to treat malaria symptoms in Haut-Ogooué Province, South-East Gabon. Materials and methods Dichloromethane and methanolic extracts of each plant were tested for their antiplasmodial activity on two chloroquine-resistant strains of Plasmodium falciparum (FCB and W2), based on lactate dehydrogenase activity. Cytotoxicity was assessed with the MTT test on MRC-5 human diploid embryonic lung cells. Results The methanolic extract of Staudtia gabonensis and the dichloromethane extract of Adhatoda latibracteata showed high antiplasmodial activity (IC50 Gabon had interesting antiplasmodial activity in vitro. This supports continued investigations of traditional medicines in the search for new antimalarial agents. The compounds responsible for the observed antiplasmodial effects are under investigation.

Salt deformation in offshore southern Gabon is represented by mobilization of an Aptian salt layer in reaction to Tertiary clastic progradation. Seismic mapping of salt bodies and associated faulting has resulted in increased understanding of the types and distribution of these salt bodies, their associated faulting patterns, and some aspects of their origin. Away from the Tertiary depocenter, the growth history of salt swells or pillows can be determined by examining onlapping and draping seismic reflectors. Significant Tertiary clastic progradation into the area mobilized the salt and resulted in a series of linear, deep salt walls and asymmetric, basinward-dipping salt rollers, commonly associated with significant up-to-basin faulting dominates the southern Gabon subbasin. The expansion history of associated sediments suggests that these faults expanded episodically throughout the Tertiary, continuing to present-day bathymetric fault scarps. The bias toward up-to-basin faults, to the apparent exclusion of down-to-basin expansion faults, remains enigmatic.

Aspergillus niger is a filamentous ascomycete fungus that is ubiquitous in the environment and has been implicated in opportunistic infections of humans. In addition to its role as an opportunistic human pathogen, A. niger is economically important as a fermentation organism used for the production of citric acid. Industrial citric acid production by A. niger represents one of the most efficient, highest yield bioprocesses in use currently by industry. The genome size of A. niger is estimated to be between 35.5 and 38.5 megabases (Mb) divided among eight chromosomes/linkage groups that vary in size from 3.5 - 6.6 Mb. Currently, there are three independent A. niger genome projects, an indication of the economic importance of this organism. The rich amount of data resulting from these multiple A. niger genome sequences will be used for basic and applied research programs applicable to fermentation process development, morphology and pathogenicity.

In the South Gabon Basin, deep multi-channel seismic reflection and gravity modeling analysis have shed light on key features of the structure of the margin. The thinned continental crust beneath the Gabon Margin appears to be composed of two distinct layers, separated by a clear, strong and more or less continuous reflector running in the 710 s TWT window. The lower crust is characterized by a higher density, intermediate between the lower values of the upper crust and the denser values of the mantle. The lower crust is irregularly shaped and presents lateral thickness variations along the direction of thinning and along the coast. In the offshore thinned continental domain, the lower and upper crust form a 2025 km thick body. Crustal thicknesses point to a relatively sharp and narrow transition, along a few tens of kilometers, between the unthinned and the thinned continental crust. The high density layer identified offshore Gabon presents similar characteristics in density, geometry and spatial distribution, as the underplated magmatic bodies observed along volcanic margins, e.g. along the South Atlantic Namibia Margin or the North Atlantic Vøring Margin. Although this lower crustal body could possibly represent ultra mafic serpentinized rocks or high grade metamorphic crustal rocks, we suggest that it could be composed of mafic rocks. Magmas resulting from partial melting during rifting may underplate the crust and/or be intruded in the lower crust through a system of dykes and sills. In this view, the present-day crustal thicknesses along rifted margins, characterized by magmatic underplating and/or intrusion, are not representative of the thinning that the crust experienced during rifting. Results of this study point to relatively shallow sedimentary basins along the South Gabon Margin. The deepest offshore depocenters located under the westernmost side of the continental platform appear to be associated with the deepest syn-rift basins These basins seem to extend along 20 to 40 km in the ~ NESW direction with a present-day average thickness of 7.3 km. Offshore Gabon, whereas the crustal thinning appears significant, the syn-rift deposit are not thick. We suggest that the area was anomalously uplifted during the rifting phase, due to an elevated thermal lithospheric gradient. The conclusions derived from our seismic and gravity analysis are consistent with the implications such a thermal anomaly would have on the tectonic evolution of a rifted margin with 1) an underplated high density lower crustal layer, 2) shallow depth syn-rift basins associated with a relatively thin crust and subsequently 3) elevated recorded subsidence rates in the initial post-rift stages.

The {approximately} 2 Ga old Oklo, Okelobondo and Bangombe natural reactors in the Republic of Gabon contain solid graphitic bitumens and clay minerals, both of which have effected the containment, or partial containment, of {sup 235}U and several fission products. In laboratory experiments, sorption of {sup 134}Cs by illite, and illite coated with petroleum was measured in aqueous NaCl solutions to simulate subsurface (connate) waters in sedimentary rocks. Elevated temperatures and increasing salinity of the NaCl solutions facilitated the removal of sorbed cesium from illite.

Abstract A cross-sectional survey was conducted to estimate the presence of leptospiral antibodies among 475 dogs from three countries of tropical Africa: Sudan (n = 62), Gabon (n = 255) and Ivory Coast (n = 158). Sixteen reference strains belonging to seven serogroups were used as antigen in the microscopic agglutination test. Overall, considering titers ?1:40, 453 samples were positive towards one or several serovars of pathogenic leptospires. Focusing on high titers, i.e. ?1:320, the seroprevalence was 40.8%. In Gabon, the seroprevalence was higher in rural areas than in an urban environment (p

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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Summary Antibody to Ebola virus was found in 14 (1.2%) of 1147 human sera collected in Gabon in 19811997. Six seropositive subjects were bled in the northeast in 1991, more than 3 years prior to recognition of the first known outbreak of Ebola haemorrhagic fever (EHF), whilst eight came from the southwest where the disease has not been recognised. It has been reported elsewhere that 98 carcasses of wild animals were found in systematic studies in northeastern Gabon and adjoining northwestern Republic of the Congo (RoC) during five EHF epidemics in August 2001 to June 2003, with Ebola virus infection being confirmed in 14 carcasses. During the present opportunistic observations, reports were investigated of a further 397 carcasses, mainly gorillas, chimpanzees, mandrills and bush pigs, found by rural residents in 35 incidents in Gabon and RoC during 19942003. Sixteen incidents had temporal and/or spatial coincidence with confirmed EHF outbreaks, and the remaining 19 appeared to represent extension of disease from such sites. There appeared to be sustained Ebola virus activity in the northeast in 19941999, with sequential spread from 1996 onwards, first westwards, then southerly, and then northeastwards, reaching the GabonRoC border in 2001. This implies that there was transmission of infection between wild mammals, but the species involved are highly susceptible and unlikely to be natural hosts of the virus.

This study will be conducted in two rural areas of the Moyen Ogooué province in Gabon, endemic for both Plasmodium falciparum and Schistosoma haematobium infections. Participants, 5 to 50 years old, will be enrol...

Two new monogenean species have been studied: Pseudodiplectanum megacirrus n.sp. and P. spinosum n.sp., branchial parasites of Galeoides decadactylus...(Bloch, 1795) (Teleostei, Polynemidae) from the coasts of Gabon

The Schisto-Calcaire Subgroup is a muddy predominantly subtidal shelf succession that crops in the West Congolian Belt. The approximately 300-m-thick CI (Bas-Congo) and approximately 20-m-thick SCIII (Gabon) se...

This is a dissertation about how Niamey, Niger is experienced in neighborhoods, through bodies, and around water. I examine the particular colonial and post-colonial historical processes that impacted development and distribution of Niamey's water...

Deposits of Robertkiri field, in the central offshore area of Niger Delta, comprise a 4 km thick succession of Pliocene to Miocene non-marine and shallow marine deposits. A sequence stratigraphic framework for Robertkiri field strata was constructed...

Seismic is of limited use in determining the presence of the Melania Formation, which is an important source rock within the presalt section of southern Gabon, because of the problems inherent to seismic imaging beneath salt. Thus, exploration efforts were concentrated on structural modeling based on gravity and magnetic data to resolve the geometry of the presalt section. An integrated interpretation of a 94-km dip profile across the Cretaceous-Holocene passive margin sequence is presented. This interpretation used a layered model of the sedimentary section down to the last reliable horizon, derived from the seismic and well data, as constrained by the gravity modeling in order to determine the approximate depth to basement. This model was then integrated, through a series of sequential steps, into a single interpretation, which satisfied all the geological and geophysical constraints needed to explain the spatial distribution of the Melania Formation.

1 The alkali soils of the middle Niger Valley Origins, formation and present evolution Laurent area of the middle Niger valley (Niger Republic), irrigation techniques had been developed to respond, 1994). The contact between the two soil types is always so abrupt that in the all West-Africa surveys

Three thermally insulated pipelines have been installed at a water depth of 35 m (115 ft) in Shell Gabon's Lucina Marine field. The three lines consist of two 2-km (1.24-mile) long flowlines connecting drilling and production platforms and a 3.2 km (2 mile) long loading line connecting a production platform to a storage tanker permanently moored in the field. All three pipelines are of 10.75-in. OD with rigid polyurethane-foam insulation contained in a high-density polyethylene sleeve. The pipelines have been designed with an operating temperature of 90/degree/C. (194/degree/F.). Thermal insulation was chosen because of the Lucina crude's high wax cloud point of 55/degree/C. (131/degree/F.). Without insulation, cooling of the crude in subsea pipelines would have lead to rapid wax deposition. Details of the coating and insulation of the line and riser pipe are given. For the line pipe, a thermal-insulation system consisting of polyurethane foam (PUF) within a polyethylene (PE) sleeve pipe was chosen.

This paper describes a two-step frac/gravel pack completion procedure conducted from a jack-up rig offshore Gabon in 1993 and 1994. After an in-depth, sand production study, seven wells were completed using hydraulic fracturing and cased-hole gravel packs. Because the Anguille formation spreads over a large gross interval, production screens of 50 to 100 m in length were used. Single-stage internal gravel packs (IGPs) on such large intervals were considered impossible to achieve with reasonable skin values. The frac-pack technique was an attractive way to achieve good proppant placement, considering that the formation being fractured would have a more homogeneous conductivity across the whole zone and a uniform proppant placement would be achieved in the perforations as well as in the annulus. High-efficiency frac gel using cross-linked HPG and a low damage one using HEC were compared to determine the best fluid to be used for these completions. Bottom hole pressures during treatment operations, as well as post-treatment pressure build-ups from each well, were analyzed in order to make general recommendations on this hydraulic fracture design.

Foreign companies engaging in business in Cameroon, Congo, Gabon, and Ivory Coast are subject to a broad range of regulations. This article deals only with those aspects of the regulations that are most important to petroleum contractors intending to engage in business in these countries. The regulator scheme actually applicable in a given case will depend on the legal structure through which a corporation operates. An American corporation may envisage engaging in business on a long-term basis through a local subsidiary or branch. On the other hand, it may wish only to perform temporary activities pursuant to one or more fixed-duration contracts with petroleum companies operating in one of countries. Each of these situations is dealt with. Common features of each area of regulation were described and the differences in regulations were presented. These topics were included: exchange control regulation, corporate forms of business association, authorization to engage in business, requirement of government or local participation in capital, investment code incentives, labor law requirements, taxation of corporations, taxation of profits, taxation of income from movable capital, taxation of amounts paid abroad as technical assistance fees, royalties and similar compensation, turnover taxes, payroll taxes, taxation of business performed without forming a local company or branch, taxation of employees and Social Security contributions. (DP)

The Mandji peninsula area is the oldest explored petroleum province in Gabon. The Clairette, Lopez North and South, N'Tchengue fields were discovered in the 50's in Senonian and Tertiary turbidites structured by salt domes. A total of 120 wells have led to a production of 12,5 MT (91 MMbls) oil. However, some gaps in the understanding of reservoir distribution and fluids regime appeared as production went on and could not be resolved with the available seismic data which was old (1974 to 1982) and irregular. A new 3D seismic survey was shot in 1992 (245 km2) over an area fringed with shallow water and mangrove forests, covered with savannah liable to flooding, and including several populated areas. The acquisition set-up was adjusted to every type of environment: Airgun in shallow water, explosive in uninhabited areas, and Vibroseis (TM) through the city of Port-Gentil. A carefully designed processing sequence led to consistently good quality throughout the survey, allowing a complete and detailed review of the area. In addition to building a coherent reference model, multi-disciplinary studies have already unveiled new opportunities : complex structural and stratigraphic components in the old fields together with unexpected structural closures and stratigraphic leads are revealed by the 3D interpretation. They will constitute new targets for further exploring an area at late production stage, and may help build a model for the exploration of the turbidites in the Senonian basin.

The Mandji peninsula area is the oldest explored petroleum province in Gabon. The Clairette, Lopez North and South, N`Tchengue fields were discovered in the 50`s in Senonian and Tertiary turbidites structured by salt domes. A total of 120 wells have led to a production of 12,5 MT (91 MMbls) oil. However, some gaps in the understanding of reservoir distribution and fluids regime appeared as production went on and could not be resolved with the available seismic data which was old (1974 to 1982) and irregular. A new 3D seismic survey was shot in 1992 (245 km2) over an area fringed with shallow water and mangrove forests, covered with savannah liable to flooding, and including several populated areas. The acquisition set-up was adjusted to every type of environment: Airgun in shallow water, explosive in uninhabited areas, and Vibroseis (TM) through the city of Port-Gentil. A carefully designed processing sequence led to consistently good quality throughout the survey, allowing a complete and detailed review of the area. In addition to building a coherent reference model, multi-disciplinary studies have already unveiled new opportunities : complex structural and stratigraphic components in the old fields together with unexpected structural closures and stratigraphic leads are revealed by the 3D interpretation. They will constitute new targets for further exploring an area at late production stage, and may help build a model for the exploration of the turbidites in the Senonian basin.

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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Twenty-four samples of uranium ore from the natural fission reactors in Gabon were studied by detailed electron microprobe analysis and backscattered electron imaging in order to determine the behavior of radiogenic Pb and fissiongenic nuclides. Lead content in uraninite varies from 19 wt% PbO in relicts of pristine uraninite, which were found only in reactor zone 10, to less than 5 wt% in altered uraninites. Different mechanisms of Pb loss from uraninite prevailed in different reactor zones and included leaching, grain boundary diffusion, exsolution via continuous precipitation, and volume diffusion. As a result of these processes, Pb content in uraninites from all the reactor zones, except for reactor zone 10, are similar and vary around a mean value of 5.2 wt% PbO. All of these processes were thermally activated and episodic. The predominance of any single mechanism in a particular reactor zone was controlled by the accessibility of solutions to the uranium ore. The thermal event which caused Pb mobilization in the deposits resulted from regional igneous activity in the Franceville Basin more than 1100 Ma after the reactors sustained spontaneous fission reactions. Reducing conditions prevented the long distance migration of Pb, as well as of fissiongenic Mo and Ru.

Abstract The usage of plants as food, cosmetics or medicinal products is common throughout the world, particularly in the traditional medicines of Africa, Asia, and South America. Despite this long-standing use, many properties of plant constituents, including their capacity to inactivate reactive oxygen species, remain unknown today. In this context, polysaccharides were isolated from barks, leaves or stems of endemic plants of Gabon by sequential extractions of crude cell walls with oxalate and KOH. Analysis of fractions indicated that pectic extracts are mainly composed of HG and RG-I in various proportions whereas hemicellulose fractions are composed of both XXXG-type xyloglucans and (1,4)-xylans substituted by 4-O-Me GlcUA residues. Antioxidant activities of these plant extracts were evaluated by monitoring their free radical scavenging activity of 2-2-diphenyl, 1-picrylhydrazyl, iron reducing capacity and metal chelating activity. Pectin from four extracts presented antioxidant activity in the DPPH assay compared to ascorbic acid (AA). These extracts also exhibited high ferric iron reducing powers compared to AA but low ferrous ion-chelating properties compared to EDTA. These activities were concentration-dependent. In contrast, commercially available pectins, xyloglucan and arabinoxylan were found to be inactive in both assays. The free scavenging activity of these molecules disappeared after enzymatic digestion and saponification, whereas the iron reducing power partially remains after these two treatments. The fact that all pectins and hemicelluloses from the three plants reacted differently suggests that specific structural motifs are involved for generation of antioxidant activity

In Gabon, CQ use was officially discontinued in 2003...pfcrt allele 76T was repeatedly measured to be 100% [1315]. The goal of this study is to investigate if this change was associated with a return of the wild...

Facility Records Annual Facility Records Annual Climate Cycle in Niger, Africa Because dust can block incoming solar energy, and because solar energy drives weather and climate, scientists around the world are looking for ways to better understand these natural phenomena. In 2006, scientists sponsored by the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility conducted a year-long field campaign in Niamey, Niger, to provide key information for the African Monsoon Multidisciplinary Analyses, or AMMA, project. During the 12-month experiment at the airport in Niamey, researchers used a portable atmospheric laboratory, airplanes, and satellites to collect information about clouds, aerosols, and solar and terrestrial energy in the skies above the site. Measurements obtained

In order to define the nature and distribution of the organic matter (OM) preserved in the modern Ogooué deep sea turbidite system (Gabon), bulk geochemical techniques (Rock-Eval pyrolysis, elemental and isotopic analyses) and palynofacies were applied to three piston cores collected in the Cape Lopez Canyon and lobe and on the continental slope, north of the canyon. The hemipelagic sedimentation in the study area is characterized by high accumulations of well-preserved OM (?23 wt. TOC %). Bulk geochemical and palynofacies analysis indicate both a marine and terrestrial origin of the OM. Contribution of the marine source is higher on the slope than in the canyon and lobe. OM accumulation in turbidites is strongly controlled by the combined influence of the Cape Lopez Canyon and littoral drift. In the canyon and lobe, turbidites show generally low TOC content (0.5 wt. %) and OM is oxidized. The origin of the OM is interpreted as both marine and terrestrial, with a higher contribution of continental source versus marine source. The low TOC contents are due to the large siliciclastic fraction transported by the littoral drift and diverted in the Cape Lopez Canyon during high energy processes (e.g. storms) which tend to dilute the OM in the turbidites. Transport by long-shore currents and/or turbiditic flows leads to oxidation of the OM. On the continental slope located north of the Cape Lopez Canyon, large amounts of OM are deposited in turbidites (up to 14 wt. %). The OM is predominantly derived from terrestrial land plants and has not been subjected to intense oxidation. These deposits are characterized by high hydrocarbon potential (up to 27 kg HC/t rock), indicating a good potential as gas-prone source rock. Because Cape Lopez Canyon captures a significant part of the sediment transported by the littoral drift, the siliciclastic sedimentary flux is reduced north of the canyon; OM is thus concentrated in the turbidites. Variation in TOC content within turbidite laminae can be explained by the burst and sweep deposition process affecting the boundary layer of the turbulent flow. This study confirms that gravity flows play a preponderant role in the accumulation and preservation of OM in deep water and that deep sea turbidite systems could be regarded as an environment where organic sedimentation occurs.

We present results of the field assessment using a total of fifteen 0.1 ha mangrove permanent sample plots (PSPs) in four selected countries in Central Africa, including: Cameroon, Gabon, Republic of Congo and De...

CLIMATOLOGY OF VERTICAL AIR MOTION DURING RAINFALL IN NIAMEY, NIGER AND BLACK FOREST, GERMANY USING in Niamey, Niger and eight months in Germany's Black Forest. The AMF includes a vertically pointing 95 GHz of the orographically influenced precipitation in Germany's mountains. __________ NOTICE: This manuscript has been

Abstract The genus Anopheles includes mosquito vectors of human malaria and arboviruses. In sub-Saharan Africa, the anopheline fauna is rich of nearly 150 species, few of which are anthropophilic and capable of transmitting pathogens to humans. Some of the remaining species are found in forests far from human environments and are vectors of wildlife pathogens. The diversity and the biology of these species have yet to be fully described. As a contribution to furthering knowledge of sylvan Anophelinae, using morphological and molecular tools we describe a new Anopheles species collected in Gabon (Central Africa), which we have named Anopheles gabonensis n. sp. We also molecularly screened this species to detect infections by Plasmodium parasites. The results showed the species to have been infected by Plasmodium vinckei, a rodent parasite. We discuss the role of An. gabonensis n. sp. in the transmission of P. vinckei in the rainforest areas of Central Africa and its potential to transfer pathogens to humans.

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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The organic-rich black shales of the Franceville Series` FB Formation overlying the uranium ores, and natural nuclear fission reactors of Oklo, Gabon, are not notably metalliferous. Chromium, gold, silver, and barium are slightly enriched in average Oklo black shale (AOK) relative to black shale standard SDO-1. Geochemical variations among the black shale samples of the sedimentary sequence include enrichment in potassium, barium, chromium, and silver in the four lowermost samples, the presence of a bleached zone depleted in organic carbon lowermost in the sequence, and elevated rare earth element (REE) content in samples closest to the Oklo reactor zones. Hydrothermal activity has influenced the geochemistry of the black shale but is evidently not linked to reactor-driven processes. Chondrite-normalized REE patterns of Oklo black shale samples show slight enrichment in light REE and slight depletion in heavy REE, especially in the sample closest to the reactor zone. However, comparison of REE content with various petrographic facies in and near the Oklo reactors shows no apparent enrichment in fission product (intermediate) REE. With few exceptions, reactor facies all contain more REE than AOK. The chondrite-normalized REE pattern of AOK resembles that of greywacke-shale turbidites of Archean greenstone belts. The paucity of uranium and manganese in AOK is a curious anomaly in an area of world class uranium and manganese deposits.

Abstract Unmetamorphosed and undeformed marine siliciclastics rocks of the FB, FC and FD of the Francevillian series (Gabon) were deposited in an epicontinental basin. Clay minerals found in black shale, siltstone and sandstone are dominantly illite and chlorite except in two levels of the FB formation, which contain smectite-rich randomly ordered mixed layers. Their survival in a 2.1 Ga old sedimentary series is not related to the abundance of organic matter (total organic carbon or TOC), nor redox conditions at the time of deposition as indicated by the Fe speciation (FeHR/FeT and FePy/FeHR ratios). Rather it results from an incomplete illitization reaction that reflects potassium deficiency. The K2O/Al2O3 ratio of shale, siltstone and sandstone vary along the series, and appear to conserve the signature of the original chemical composition of the rocks. K-feldspars which are present in the FC and FD formations are missing in the FB formation. Consequently, the smectite layers do not appear to be inherited from a detrital input in the basin but must be considered as representative of an intermediate stage of the illitization reaction reached during diagenesis.

Abstract A prospective, descriptive, analytic study was conducted at the Centre Hospitalier de Libreville in Gabon between February and September 2013 to evaluate acceptance of long-acting reversible contraceptives (LARC) and depot-medroxyprogesterone acetate (DMPA) following abortion. Women received counseling on the combined oral pill, DMPA, copper intrauterine devices (IUDs), and implants. The association between sociodemographic and clinical characteristics, knowledge of contraceptives, and acceptance was analyzed. Of the 383 women admitted with abortion complications, 206 (53.7%) knew of no systemic contraceptives. The best-known method was the oral pill (42.0%). Only 14 women (3.6%) knew of a LARC method (IUD or implants) and only 2 (0.5%) said the injectable was their best-known method. Over 90% accepted a modern contraceptive method after abortion. Two-thirds (66.8%) chose the pill, 14.6% DMPA, and 9.3% a LARC method. Only 9.1% of the women refused to initiate use of any method.

Abstract Surficial formations in Gabon, as well as in other places of western Central Africa include a ubiquitous, homogeneous and 13 m-thick clayey to sandy lateritic surface cover known as the Cover Horizon. From 14C radiometric dating it has been concluded that the emplacement of this unit was correlative with a major environmental crisis which affected Central Africa c. 30002000 years ago. 10Be and Nd-isotopic analyses have been performed to provide new constraints on the age and origin of this layer. Six samples from two depth profiles investigated for 10Be exhibit an almost constant concentration consistent with a very recent deposition age. Nd-isotopic analyses performed on the silt to clay fraction of eleven samples from widely spaced locations over Gabon attest for mildly radiogenic signatures (?Nd = ?23 to ?17) in ten of them, and a slightly radiogenic signature (?Nd = ?9) in one sample. TDM model ages range from 1.6 to 2.6 Ga, and a perfect discrimination is observed between the Nd-isotopic signature of the Cover Horizon and that of the underlying Congo Craton. This makes an aeolian origin as the most probable for the Cover Horizon. The average ?Nd (c. ?20) is however rather unusual for aeolian sediments or aerosols. A possible source of particles is therefore tested by considering the present-day atmospheric flux over Gabon and adjacent regions. Combined atmospheric modeling and Nd-isotopes leads to the conclusion that the fine fraction of the Cover Horizon could have originated from the northern part of the Namib desert.

The discovery of naturally occurring fission reactors in the rock strata of the Paleoproterozoic Francevillian Basin in the Republic of Gabon in equatorial West Africa led to several programs to define migration and/or retention of uranium and fissiogenic isotopes from/in the natural reactor zones. Although much understanding has been gained, new insight is needed regarding the chemical and physical parameters that control movement and retention of fission products over almost two billion years from/in the natural reactors. Seventeen known natural fission reactors sustained criticality for 0.1 to 1 million years in hydrothermally altered sedimentary rocks 1968 +/- 50 million years ago. These natural nuclear reactors attained criticality because of high concentrations of uranium in small pockets in uranium ores, the lack of neutron poisons, and because at the time they reached criticality, the abundance of [sup 235]U was five times greater than it is today. Water acted as a moderator, and temperature in the natural reactors was between 160 and 360[degrees]C. Both the uranium-rich pockets and the uranium ore bodies in which these pockets are located were formed when aqueous solutions moving through highly fractured zones in the Francevillian sedimentary rocks met organic-rich sediments. This resulted in the reduction of U(VI) in the dissolved uranyl ions to U(IV), causing the precipitation of pitchblende and uraninite. It has been proposed that between 2.2 and 1.9 billion years ago, the earth's atmosphere experienced a remarkable temporary rise in O[sub 2] content; this event may account for the uranium-bearing, oxidizing aqueous solutions in the Francevillian rocks.

A total of about forty core samples representing an almost two kilometer thick, lacustrine sedimentary sequence of Neocomian age in the south Gabon basin was analysed for its hydrocarbon generation potential, maturity and further organic matter characteristics. Organic carbon concentrations are variable and not particularly high (0.4-5%), but the organic matter is hydrogen-rich. This hydrogen-richness finds its expression in high hydrogen indices (about 600 to 700 mg hc/g TOC) which decrease with increasing maturation. According to pyrolysis experiments, hydrocarbon generation from the immature sediments is predicted to begin only at temperatures greater than 100{degrees}C and reaches a maximum only at temperatures greater than 150{degrees}C, because the organic material possesses a very high thermal stability. Such a high thermal stability was already established for lacustrine organic matter from some other deposits (e.g. Green River oil shales) and is certainly an important factor for the evaluation of hydrocarbon potentials in lacustrine basins. The maturity of the organic matter changes from immature to mature with increasing depth. Peak oil generation stage was almost reached by the deepest samples as indicated by a variety of optical and geochemical parameters. Generated petroleum should be wax-rich and rather poor in gas, except if oil to gas cracking occurs within the source rocks. With respect to molecular geochemistry, several interesting pecularities were found. As an example, variable distributions of several unknown tetracyclic terpanes (molecular formula C{sub 24}H{sub 42}) were detected in the samples of lower maturity. Two series of terpane pseudohomologues occur in the more mature samples, one of which is assumed to consist of diahopanes, the other yet remaining unknown. These compounds seem to be widely distributed in lacustrine sediments of higher maturity, thus possibly representing maturity and/or facies indicators.

Abstract 3-D seismic reflection data has enabled the documentation of a system of remarkable modern and buried u-shaped gullies which intimately co-exist with upslope migrating sediment waves along 80 km of the Gabon continental slope. The modern gullies occur on a silty mud-dominated slope in water depths of 1501500 m on an ~ 50 km wide slope with a gradient of 4.5° decreasing to 1.5°. The gully sets persist laterally for distances of at least 40 km and extend downslope for distances of up to 60 km. The gullies are u-shaped in cross-section, with a relief of 530 m, and widths of 50400 m. Intriguingly, the gullies become narrower and shallower with distance down the slope, as well as increasing in number down slope. The majority of the gullies appear to be erosional but some appear to have resulted from simultaneous aggradation along inter-gully ridges and non-deposition along the adjacent gully floor. Hence, these gullies are interpreted to have formed mainly in response to spatially-variable deposition, rather than erosion. Upslope migrating sediment waves occur in close proximity to the gullies. Gullies cross fields of sediment waves and waves are observed to migrate up-slope locally within both the erosional and aggradational gullies. Evidence is lacking for any slumping or headward erosion in the headwall region of the gullies, which discounts formation by very local sediment gravity flows originating from shelf-edge collapse, as has been observed in other v-shaped gully systems. Based on our new data, and supported by theoretical studies on the mechanics of turbidity currents, we propose that the gullies and related sediment waves were formed by diffuse, sheet-like, mud-rich turbidity currents that presumably originated on the shelf. Instabilities in the turbidity currents generated a wave-shaped perturbation in a cross-flow direction leading to regularly spaced regions of faster and slower flow. For the non-aggradational and erosional gullies it is inferred that gully axes experienced flow velocities that mainly exceeded the settling velocity of the sediment in suspension, and thus no deposition occurred. In contrast, the aggradational gullies indicate lower flow velocities with sediment deposition both within the gully axes and on the gully flanks. Mixed mode gullies are also found which indicate that successive flows can experience variations in flow properties leading to interspersed erosional and depositional events.

RESPONSE OF PEARL MILLET [(Pennisetum americanum L. (Schum) ] TO SOIL MOISTURE IN ONE AGROCLIMATOLOGICAL ZONE OF NIGER, WEST AFRICA A Thesis by Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1988 Major subject: Soil Science RESPONSE OF PEARL MILLET [Pennisetum americanum L. (Schum) ] TO SOIL MOISTURE IN ONE AGROCLIMATOLOGICAL ZONE OF NIGER, WEST AFRICA A Thesis by Approved as to style...

Recent field and subsurface data about the early Neocomian Ndombo series and the Neocomian to mid-Barremian Schistes series of the interior basin of Gabon further our understanding of the initial stages of early Cretaceous N4060°E extensional rifting. The syn-rift series comprise fluviallacustrine claystonessandstones, rare conglomerates, and carbonates. The syn-rift fill begins with braided-stream feldspathic sandstones. These are overlain first by fluviallacustrine deposits and then by predominantly lacustrinepalustrine claystones, which are potential petroleum source rocks. The claystones are eroded in part and are capped by the pre-Aptian angular unconformity marking the end of Cretaceous rifting in the interior basin. This change in syn-rift facies and depositional environments reflects a rise in base level in response to accelerated subsidence after the initial stage of rifting. The syn-rift deposits form two fining-upward sequences several 1001000 m thick.

The importance of human activity and ecological features in influencing African forest elephant ranging behaviour was investigated in the RabiNdogo corridor of the Gamba Complex of Protected Areas in southwest Gabon. Locations in a wide geographical area with a range of environmental variables were selected for patch-occupancy surveys using elephant dung to assess seasonal presence and absence of elephants. Patch-occupancy procedures allowed for covariate modelling evaluating hypotheses for both occupancy in relation to human activity and ecological features, and detection probability in relation to vegetation density. The best fitting models for old and fresh dung data sets indicate that (1) detection probability for elephant dung is negatively related to the relative density of the vegetation, and (2) human activity, such as presence and infrastructure, are more closely associated with elephant distribution patterns than are ecological features, such as the presence of wetlands and preferred fresh fruit. Our findings emphasize the sensitivity of elephants to human disturbance, in this case infrastructure development associated with gas and oil production. Patch-occupancy methodology offers a viable alternative to current transect protocols for monitoring programs with multiple covariates.

Abstract We report new geochemical data for the volcanic and subvolcanic rocks associated with the evolution of the Francevillian basin of eastern Gabon during Paleoproterozoic times (c. 2.12 Ga). Filling of this basin has proceeded through four main sedimentary or volcano-sedimentary episodes, namely FA, FB, FC and FD. Volcanism started during the FB episode being present only in the northern part of the basin (Okondja sub-basin). This volcanism is ultramafic to trachytic in composition and displays a rather constant alkaline geochemical signature. This signature is typical of a within-plate environment, consistent with the rift-setting generally postulated for the Francevillian basin during the FB period. Following FB, the FC unit is 1020 m-thick silicic horizon (jasper) attesting for a massive input of silica in the basin. Following FC, the FD unit is a c. 200400 m-thick volcano-sedimentary sequence including felsic tuffs and epiclastic rocks. The geochemical signatures of these rocks are totally distinct from those of the FB alkaline lavas. High Th/Ta and La/Ta ratios attest for a calc-alkaline signature and slight fractionation between heavy rare-earth suggests melting at a rather low pressure. Such characteristics are comparable to those of felsic lavas associated with the Taupo zone of New Zealand, a modern ensialic back-arc basin. Following FD, the FE detrital unit is defined only in the Okondja region, probably associated with a late-stage collapse of the northern part of the basin. It is suggested that the alkaline to calc-alkaline volcanic transition reflects the evolution of the Francevillian basin from a diverging to a converging setting, in response to the onset of converging movements in the Eburnean Belt of Central Africa.

The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. To achieve this goal, ARM scientists and researchers around the world use continuous data obtained through the ARM Climate Research Facility. The ARM Mobile Facility (AMF) operates at non-permanent sites selected by the ARM Program. Sometimes these sites can become permanent ARM sites, as was the case with Graciosa Island in the Azores. It is now known as the Eastern North Atlantic permanent site. In January 2006 the AMF deployed to Niamey, Niger, West Africa, at the Niger Meteorological Office at Niamey International Airport. This deployment was timed to coincide with the field phases and Special Observing Periods of the African Monsoon Multidisciplinary Analysis (AMMA). The ARM Program participated in this international effort as a field campaign called "Radiative Divergence using AMF, GERB and AMMA Stations (RADAGAST).The primary purpose of the Niger deployment was to combine an extended series of measurements from the AMF with those from the Geostationary Earth Radiation Budget (GERB) Instrument on the Meteosat operational geostationary satellite in order to provide the first well-sampled, direct estimates of the divergence of solar and thermal radiation across the atmosphere. A large collection of data plots based on data streams from specific instruments used at Niamey are available via a link from ARM's Niamey, Niger site information page. Other data can be found at the related websites mentioned above and in the ARM Archive. Users will be requested to create a password, but the plots and data files are free for viewing and downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compels additional exploration. We therefore undertook whole genome sequencing of the acidogenic A. niger wild type strain (ATCC 1015), and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was utilized to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 megabase of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis revealed up-regulation of the electron transport chain, specifically the alternative oxidative pathway in ATCC 1015, while CBS 513.88 showed significant up regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases and protein transporters.

Protein glycosylation is known to play an essential role in both cellular functions and the secretory pathways; however, little information is available on the dynamics of glycosylated N-linked glycosites of fungi. Herein we present the first extensive mapping of glycosylated N-linked glycosites in industrial strain Aspergillus niger by applying an optimized solid phase enrichment of glycopeptide protocol using hydrazide modified magnetic beads. The enrichment protocol was initially optimized using mouse plasma and A. niger secretome samples, which was then applied to profile N-linked glycosites from both the secretome and whole cell lysates of A. niger. A total of 847 unique N-linked glycosites and 330 N-linked glycoproteins were confidently identified by LC-MS/MS. Based on gene ontology analysis, the identified N-linked glycoproteins in the whole cell lysate were primarily localized in the plasma membrane, endoplasmic reticulum, golgi apparatus, lysosome, and storage vacuoles. The identified N-linked glycoproteins are involved in a wide range of biological processes including gene regulation and signal transduction, protein folding and assembly, protein modification and carbohydrate metabolism. The extensive coverage of glycosylated N-linked glycosites along with identification of partial N-linked glycosylation in those enzymes involving in different biochemical pathways provide useful information for functional studies of N-linked glycosylation and their biotechnological applications in A. niger.

Abstract The Malaria Pf Rapid Test Device Acon® (Acon Labs) and the pan HRP2/aldolase RDT, Malaria P.f/Pan Rapid Test Device Acon® (Acon Labs), performances were evaluated for malaria species diagnosis in 592 febrile patients living in Gabon using microscopy as gold standard. Sensitivities were equal or above 96.0% for Plasmodium falciparum detection, of 62.5% for nonP. falciparum malaria species detection and higher in younger children (100%). Negative predictive values were greater than 97.0%. Acon®HRP2 had a higher specificity (96.6%) and lower false-positive (FP) rate (9.3%) compared to Acon®Pf/Pan, which had a specificity of 87.3% and a FP rate of 27.1% (P < 0.01). Overall, 32.5% of all Acon® Pf/Pan tests resulted in a faint band with only 2 resulted from samples with a parasitemia below 100 p/?L. The accuracy of Acon®HRP2 RDT for the diagnosis of P. falciparum infection is confirmed. However, the high FP rate observed with Acon®Pf/Pan is a limitation for its use.

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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Natural nuclear fission reactors are only known in two uranium deposits in the world, the Oklo and Bangombe deposits of the Franceville basin: Gabon. Since 1982, five new reactor zones have been discovered in these deposits and studied since 1989 in a cooperative European program. New geological, mineralogical, and geochemical studies have been carried out in order to understand the behavior of the actinides and fission products which have been stored in a geological environment for more than 2.0 Ga years. The Franceville basin and the uranium deposits remained geologically stable over a long period of time. Therefore, the sites of Oklo and Bangombe are well preserved. For the reactors, two main periods of actinide and radionuclides migration have been observed: during the criticality, under P-T conditions of 300 bars and 400-500{degrees}C, respectively, and during a distention event which affected the Franceville basin 800 to 900 Ma ago and which was responsible for the intrusion of dolerite dikes close to the reactors. New isotopic analyses on uranium dioxides, clays, and phosphates allow us to determine their respective importance for the retention of fission products. The UO{sub 2} matrix appears to be efficient at retaining most actinides and fission products such as REEs, Y, and Zr but not the volatile fission products (Cd, Cs, Xe, and Kr) nor Rb, Sr, and Ba. Some fissiogenic elements such as Mo, Tc, Ru, Rh, Pd, and Te could have formed metallic and oxide inclusion in the UO{sub 2} matrix which are similar to those observed in artificial spent fuel. Clays and phosphate minerals also appear to have played a role in the retention of fissiogenic REEs and also of Pu. 82 refs., 21 figs., 12 tabs.

in the Niger Delta. The upper Miocene D-07, D-08 and E-01 oil sands comprise a series of stacked hydrocarbon reservoirs in Block 2 of Meren field. These reservoir sandstones were deposited in offshore to upper shoreface environments. Seven depositional... (offshore marine facies). Lithofacies have distinct mean petrophysical properties, although there is overlap in the range of values. The highest quality reservoir deposits are cross-bedded sands that were deposited in high-energy upper shoreface...

The weakly electric fish, Gathonemus niger, discharged with a frequency of 4 to 8 Hz during the day and 10 to 16 Hz during the night. The frequency of superimposed burst discharges (32 to 56 Hz) was independent of diurnal factors. The variation of the electric organ discharge frequency during the day was investigated in response to controlled electric stimulus patterns: (a) A free running stimulus frequency of 4 Hz, simulating the resting frequency of another fish, and different stimulus intensities, simulating different distances between two fish. (b) Free running frequencies of 4, 8, 16, , 128 Hz and two particular stimulus intensities. (c) Discharge coupled stimuli (each discharge triggered an electric stimulus with a fixed delay) and different stimulus intensities. All three kinds of stimuli elicited defined and predictable response discharge patterns supporting the assumption that an electric fish would respond to a particular discharge pattern of another fish also in a similar and predictable manner. Low stimulus intensities (0·04 to 0·2 mV per cm) caused cessation of the discharge activity, a hiding or listening response. The discharge rate increased linearly with the logarithm of the stimulus intensity. The fish was particularly sensitive to stimulus frequencies which simulated its burst activity (32 to 56 Hz). Discharge coupled stimuli showed that the fish responded to about eight times lower stimulus intensities if the stimulus occurred between two discharges (15 to 30 m-s after the fish's discharge) than if the stimulus occurred within or immediately after the discharge. All suprathreshold stimuli elicited a typical discharge pattern: The irregular resting discharge activity became significantly regular. The degree of regularity was even improved during maintained stimulation. The regularisation of the discharge activity is thought to be involved in the fish's electrolocating system whereas frequency variations are considered as being involved in both the locating system and as communication signals among weakly electric fish.

Political instability and corruption is the rule, rather than the exception, in Africa`s main producing regions, but exploration and production prospects there are bright and attractive to foreign operators. The paper discusses exploration, drilling, resource development, and production in Nigeria, Libya, Algeria, Egypt, Angola, Congo, Gabon, and Tunisia. The other countries of Africa are briefly mentioned, i.e., Cameroon, Cote D`Ivoire, South Africa, Sudan, Namibia, Equatorial Guinea, Eritrea, Zaire, Mozambique, Ghana, Niger, and Seychelles.

This book discusses the detailed geology of the four divergent margin basins and establishes a set of analog scenarios which can be used for future petroleum exploration. The divergent margin basins are the Campos basin of Brazil, the Gabon basin, the Niger delta, and the basins of the northwest shelf of Australia. These four petroleum basins present a wide range of stratigraphic sequences and structural styles that represent the diverse evolution of this large and important class of world petroleum basins.

The history of uranium development in Africa is briefly summarized. Today there are 4 major uranium producing countries in Africa: Gabon, Niger, Namibia, and South Africa. These nations have the possibility of political instability. In addition, the uranium market has undergone a series of radical changes over the past decade. How these African nations have responded to this changing market, and how their roles in the international market relate to domestic political and economic factors are the topics of this report. (DMC)

In areas where malaria is endemic, pregnancy is associated with increased susceptibility to malaria. It is generally agreed that this risk ends with delivery and decreases with the number of pregnancies. Our stud...

An analysis of the petroleum geology of the Ogooue Delta region reveals the presence of two independent petroleum systems. The first system appears to have been generated from a pre-Cenomanian restricted marine source. These oils are largely reservoired in Batanga Formation sandstones (Maastrichtian) and are deposited principally along the southern margin of the delta. The second system appears to have been generated from the Azile and Anguille Formations (Senonian). These Upper Cretaceous oils are reservoired principally within Anguille reservoirs. These accumulations appear geographically less restricted, but appear most concentrated within the northern portion of the delta. The geographic distribution of the two systems appears to be controlled by several factors including the distribution of the oil-prone source, the nature of migration network, and the level of thermal maturity. The pre-Cenomanian system appears to have a more effective mechanism for vertical migration than the Azile-Anguille sourced system. It is unclear as to why differences in the migration network should exist within a single delta complex. Although the two systems have different source rocks they both share one major controlling factor. In both cases the areal limit of the petroleum system is constrained by thermal maturation. The overburden associated with the delta complex provided for the appropriate levels of thermal maturation. Modeling results suggest that the pre-Cenomanian system began generating liquid hydrocarbons during the Oligocene. The Senonian system began generating hydrocarbons during the Miocene. Both systems are still actively generating hydro- carbons.

Amphibian chytridiomycosis is an infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd) that is implicated in the worldwide decline and extinction of amphibians. Africa has been proposed as a...

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "gabon mauritania niger" from the National Library of EnergyBeta (NLEBeta).
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12 localities in Gabon, West-Central Africa from 1998 to 2009. We measured time, slope, and voltage-negative pre- potential, P0. Both factors varied clinally across Gabon. EODs are shorter in eastern Gabon and longer in western Gabon. Peak P0 is slightly larger in northern Gabon and smaller in southern Gabon. P0

and electric organ discharge (EOD) signals from 553 specimens col- lected from 12 localities in Gabon, West factors varied clinally across Gabon. EODs are shorter in eastern Gabon and longer in western Gabon. Peak P0 is slightly larger in northern Gabon and smaller in southern Gabon. P0 in the EOD is due

The emergence and spread of Plasmodium falciparum resistance to almost all available antimalarial drugs necessitates the search for new chemotherapeutic compounds. The ubiquitin/proteasome system plays a major ro...

The emergence of Human retroviruses, in Central Africa, may occur in contact with non human primates, during hunting and butchering. Recent studies described several cases of human infections with Human T-cell Ly...

Coastline mapping is of great interest in many different applications. In this Letter, we analyse the effect of the polarization and the incidence angle of the new Advanced Synthetic Aperture Radar (ASAR) sensor on coastline detection. Results indicate ...

Physicians depend on reliable information on the local epidemiology of infection and antibiotic resistance rates to guide empiric treatment in critically ill patients. As these data are scarce for Central Africa,...

Of the sixteen known Oklo and the Bangombe natural fission reactors (hydrothermally altered elastic sedimentary rocks that contain abundant uraninite and authigenic clay minerals), reactors 1 to 6 at Oklo contain only traces of organic matter, but the others are rich in organic substances. Reactors 7 to 9 are the subjects of this study. These organic-rich reactors may serve as time-tested analogues for anthropogenic nuclear-waste containment strategies. Organic matter helped to concentrate quantities of uranium sufficient to initiate the nuclear chain reactions. Liquid bitumen was generated from organic matter by hydrothermal reactions during nuclear criticality. The bitumen soon became a solid, consisting of polycyclic aromatic hydrocarbons and an intimate mixture of cryptocrystalline graphite, which enclosed and immobilized uraninite and the fission-generated isotopes entrapped in uraninite. This mechanism prevented major loss of uranium and fission products from the natural nuclear reactors for 1.2 b.y. 24 refs., 4 figs.

Insecticide-treated bed nets (ITNs) range among the most effective measures of malaria prophylaxis, yet their implementation level in sub-Saharan Africa is still low. The goal of this study was to investigate the...

Tuberculosis constitutes a substantial health problem in Africa [1], particularly in the face of the human immunodeficiency virus (HIV) co-pandemic and the increasing problem of drug-resistant Mycobacterium tuber...

Although a substantial decline of Plasmodium falciparum...infection is observed in Africa following implementation of new control strategies, malaria is still considered as the major cause of febrile illness in h...

New mineralogical and isotopic studies were carried out on samples form the Bangombe natural nuclear reactor. This reactor is located at shallow depth in the weathering profile and has been subjected to severe supergene alteration. Textural evidence indicates partial dissolution of uraninite in the Bangombe ore related to precipitation of Fe-Ti oxyhydroxides and clay minerals (kaolinite and metahalloysite). As a consequence of the alteration of the uraninite, uranium and fissiogenic rare earth elements were released in the clayey border of the reactor, whereas radiogenic {sup 232}Th remained confined in the close vicinity of the core. A retention effect is also evidenced, under reducing conditions, in the black shales located above the reactor.

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Nosocomial infections pose substantial risk to patients receiving care in hospitals. In Africa, this problem is aggravated by inadequate infection control due to poor hygiene, resource and structural constraints,...

This mineralogical study was completed to elucidate the relationships between uranium distribution and alteration products of the host rock of natural reactor zone clays just below the reactor core. Uraninite is preserved without any alteration in the reactor core. Uranium minerals are found to be present in the fractures in the reactor zone clays associated with iron-mineral veins, galena and Ti-bearing minerals. Uranium, for which the phases could not be identified, occurs in iron-mineral veins and the iron-mineral rim of pyrite grains in the reactor zone clays. Uranium is not associated with granular iron minerals occurring in the illite matrix of the reactor zone clays. The degree of crystallinity and uranium content of the three iron-bearing alteration products suggest that they formed under different conditions; the granular iron minerals, under alteration conditions where uranium was not mobilized while the iron-mineral veins and the iron-mineral rim of pyrite, under conditions in which uranium is mobilized after the formation of the granular iron minerals.

Following the deployment of new recommendations for malaria control according to the World Health Organization, an estimation of the real burden of the disease is needed to better identify populations at risk and...

Several factors can determine the outcome of a malarial infection. Studies on susceptibility or resistance to malarial infection can be confounded by differences in transmission. In the present study, the rel...

Florecite-(La) (La/Ce = 1.09) with fissiogenic REEs and florecite-(Ce) (La/Ce = 0.62) have been identified in illite from the clay mantle surrounding a natural, 2 Ga fission reactor at Bangombre and in sandstone beneath the reactor zone, respectively. Florencite-(Ce) is apparently unrelated to nuclear processes and occurs with monazite-(Ce), apatite, TiO{sub 2} (probably anatase), zircon, and illite. Grains of florencite-(Ce) contain inclusions of thorite, chalcopyrite, and galena. Florencite-(La) was found 5 cm from the {open_quotes}core{close_quotes} of the reactor and contains inclusions of galena and U-Ti-bearing phases. Secondary uraninite and coffinite have precipitated on some of the florencite grains. The chemical composition of florencite-(La) as determined by electron microprobe analysis is (La{sub 0.38}Ce{sub 0.35}Nd{sub 0.06}Sm{sub 0.01}-Ca{sub 0.03}Sr{sub 0.17})(Al{sub 2.98}Fe{sub 0.02}{sup 3+})(PO{sub 4})[PO{sub 3.80}(OH){sub 0.20}](OH){sub 6}. Secondary ion mass spectrometry revealed that between 27 and 30% of Nd and 67 and 71% of Sm in florencite-(La) is fissiogenic. The presence of fissiogenic REEs in {open_quotes}florencite{close_quotes} from the reactor zone in Bangombe and their preferential concentration in florencite relative to the bulk sample of clay demonstrate that aluminous phosphates may have played a more significant role in the fixation of fissiogenic REES released from uraninite after the sustained fission reactions than sorption onto clays. 30 refs., 3 figs., 2 tabs.

Industry now has drilled many wells in water depths of from 2000 to 5000 ft offshore countries like Canada, Surinam, Australia, UK, Spain, Ivory Coast, Nigeria, Gabon, Brazil, Mauritania, Indonesia, Morocco and Ireland. The US has the world's best technology and the world's best experience and most of the world's proven deepwater drilling equipment and contractors are in the US. However, the US has not released for exploration its deepwater areas. The OCS out to 600+ ft is being exlored in a routine manner by mobile, bottom-supported and floating drilling equipment. The continental slope (600 to 5000 ft.) is being explored by the special deepwater floating drilling units. The continental rise (5000 to 13,000 ft.) is industry's next objective for exploration. The technology and experience used in exploration drilling is applied to producing oil/gas in deepwater. Production is handled by a floating platform resembling a semi drilling rig with a production riser substituting for the drilling riser. Industry takes small, steady steps to develop its techniques for drilling and producing. (DP)

graduate committee, Dr. Larry Wilding, for pedongenic interpretations, and Dr. Andrew Manu for lending an ear and helping me construct and demolish one hypothesis after another. My thanks also go to the Institut National de Recherches Agronomiques du...

Can architecture catalyze economic growth? This thesis serves as a design contribution to the war against poverty by proving that small-scale architectural interventions can propagate large-scale economic growth. It ...

of air at the surface is relatively facile. Hydraulic Conductivity Redistribution of soil water affects plant growth, and the rate and duration of internal moisture flow determines 19 effective soil water storage. This is important to remember when... in sorption (wetting). This characteristic of wetting versus drying for a soil is known as the hysteresis effect (Lal 1979a). Hillel (1980) notes that hysteresis is important for coarse-textured soils in the process of redistribution of soil water...

Effect Solar System Conventional Sources of Power Types of Renewable Energies Solar Energy Passive and infinite of resources such as Solar, wind, geothermal, etc... that are either under exploited) Water Cycle (Followed by Water Resources' Manager Talk) Global Warming Green House EffectGreen House

of variability of the long-term fundamental physical constants [5,6] to storage of nuclear wastes in geological on how to retain nuclear wastes, including fission Xe and Kr, and prevent uncontrolled runaway chain

Using selective laser extraction technique combined with sensitive ion-counting mass spectrometry, we have analyzed the isotopic structure of fission noble gases in U-free La-Ce-Sr-Ca aluminous hydroxy phosphate associated with the 2 billion yr old Oklo natural nuclear reactor. In addition to elevated abundances of fission-produced Zr, Ce, and Sr, we discovered high (up to 0.03??cm3???STP/g) concentrations of fission Xe and Kr, the largest ever observed in any natural material. The specific isotopic structure of xenon in this mineral defines a cycling operation for the reactor with 30-min active pulses separated by 2.5 h dormant periods. Thus, nature not only created conditions for self-sustained nuclear chain reactions, but also provided clues on how to retain nuclear wastes, including fission Xe and Kr, and prevent uncontrolled runaway chain reaction.

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This study prospectively observed the efficacy of artemether-lumefantrine for the treatment of uncomplicated non-falciparum or mixed-species malaria in two routine district hospitals in the Central African countr...

SIV and STLV were detected by antibodies to HIV and HTLV antigens, and PCRs were performed on samples with an HIV or/and HTLV-like or indeterminate profile. Fourteen percent of the samples cross-reacted with H...

In an underground nuclear waste repository, the chemical behavior of some stored fission products and actinides depends on the redox conditions during their long-term evolution. In this respect, radiolysis is an important phenomenon which can significantly modify the local redox conditions. The Oklo natural fission zones are good examples where the effect of radiolysis can be deduced from a mineralogical and geochemical study. Zones 10 and 16 were studied because they are located at depth of 270 m in an area devoid of any recent water circulation and not subject to the effect of the lateritic alteration occurring elsewhere in this area. In zone 10, there is a marked evolution of the U-Pb-Fe-S mineralogy from the center to the periphery of the reactor zone. In the center, uraninite shows silicification and coffinitisation with the formation of galena and native lead; the PbO content of uraninite can be as much as 20 wt%. In the periphery of the reactor zone, some radiogenic lead is present as minimum (Pb{sub 3}O{sub 4}) and in Pb-bearing calcite. In the surrounding sandstones, hematite is widespread. In zone 16, the mineral paragenesis is generally comparable with that of zone 10 but with some differences. Galena is the only Pb-bearing mineral associated with uraninite crystals. The PbO content of uraninite is always <7 wt%. In the periphery of the alteration zone, barite partly replaces quartz. In the reactor zone, hematite is sometimes replaced by pyrite. In an area where the fission zone 10 is in contact with sandstones devoid of organic matter, H{sub 2}O-H{sub 2} {+-} CH{sub 4} inclusions were observed in healed microcracks in the detrital quartz grains. Based on microthermometric measurements, the salinity of the aqueous solution ranges from 0.2 to 18 wt% eq. NaCl. Raman analysis of the gas phase indicates that the hydrogen to oxygen ratio differs from an inclusion to the other. 41 refs., 15 figs., 3 tabs.

The presence, concentration, and distribution of organic free radicals as well as their association with specific surface areas and microporosities help characterize the evolution and behavior of the Oklo carbonaceous matter. Such information is necessary in order to evaluate uranium mineralization, liquid bitumen solidification, and radio nuclide containment at Oklo. In the Oklo ore deposits and natural fission reactors carbonaceous matter is often referred to as solid graphitic bitumen. The carbonaceous parts of the natural reactors may contain as much as 65.9% organic C by weight in heterogeneous distribution within the clay-rich matrix. The solid carbonaceous matter immobilized small uraninite crystals and some fission products enclosed in this uraninite and thereby facilitated radio nuclide containment in the reactors. Hence, the Oklo natural fission reactors are currently the subjects of detailed studies because they may be useful analogues to support performance assessment of radio nuclide containment at anthropogenic radioactive waste repository sites. Seven carbonaceous matter rich samples from the 1968 {+-} 50 Ma old natural fission reactors and the associated Oklo uranium ore deposit were studied by electron spin resonance (ESR) spectroscopy and by measurements of specific surface areas (BET method). Humic acid, fulvic acid, and fully crystalline graphite standards were also examined by ESR spectroscopy for comparison with the Oklo solid graphitic bitumens. With one exception, the ancient Oklo bitumens have higher organic free radical concentrations than the modem humic and fulvic acid samples. The presence of carbon free radicals in the graphite standard could not be determined due to the conductivity of this material. 72 refs., 7 figs., 1 tab.

Uraninites from the Bangombe natural fission reactor (RZB) and normal uranium-ore occur as fine veins in the sandstone host-rock as well as altered, broken, and slightly displaced grains in an illitic matrix, and in nodules and veins of solid bitumen. Inclusions of galena, (Y,Gd)-rich phosphates, a Pb-oxide and a Ti-oxide? were observed. Uraninites just below RZB were partially altered to a uranyl-sulfate. Three generations of uraninite were identified based on their PbO-contents of 8--11.06 wt%, 6 wt% (the largest population), and a younger generation with 3 wt%. Diffusional loss of Pb is indicated by the presence of a Pb-oxide at the interface to the uraninites. The behavior of the metallic fission products, incompatible with the uraninite structure, may mimic the behavior of Pb in these uraninites. The averaged impurity-content ranges from 4.29 to 6.89 wt%, and consists mainly of SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, FeO, CaO, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5}. The averaged content of Y{sub 2}O{sub 3} and the Ln`s is less than 0.78 wt% and there is a scattered positive correlation with P{sub 2}O{sub 5}. The content of Y + Ln`s is generally highest in the uraninites from RZB. Uraninite hydration and the formation of uranopelite/zippeite have caused complete loss of Y and the Ln`s. The analytical results indicate that Y and the Ln`s, which are high yield fission products, may be released from uraninite during alteration in the presence of P.

A geochemical and biological marker investigation of a variety of oils from offshore Brazil and west Africa, ranging in age from Lower Cretaceous to Tertiary, has been done, with the following aims: (1) assessing the depositional environment of source rocks, (2) correlating the reservoired oils, (3) comparing the Brazilian oils with their west African counterparts. The approach was based in stable isotope data; bulk, elemental, and hydrous pyrolysis results; and molecular studies involving quantitative geological marker investigations of alkanes using GC-MS and GC-MS-MS. The results reveal similarities between groups of oils from each side of the Atlantic and suggest an origin from source rocks deposited in five types of depositional environment: lacustrine fresh water, lacustrine saline water, marine evaporitic/carbonate, restricted marine anoxic, and marine deltaic. In west Africa, the Upper Cretaceous marine anoxic succession (Cenomanian-Santonian) appears to be a major oil producer, but in Brazil it is generally immature. The Brazilian offshore oils have arisen mainly from the pre-salt sequence, whereas the African oils show a balance between origins from the pre-salt and marine sequences. The integration of the geochemical and geological data indicate that new frontiers of hydrocarbon exploration in the west African basins must consider the Tertiary reservoirs in the offshore area of Niger Delta, the reservoirs of the rift sequences in the shallow-water areas of south Gabon, Congo, and Cuanza basins, and the reservoirs from the drift sequences (post-salt) in the deep-water areas of Gabon, Congo Cabinda, and Cuanza basins.

is therefore of great importance for future optimisation of heterologous protein production in the fungus into smaller molecules that can be taken up and serve as energy and nutrient sources, the fungus successfully exploited for the production of homologous and other fungal enzymes, the expression

TO THE BENEFIT OF BOTH An hour after sunset on his last night in the west African country of Gabon, UF graduate Gabon's unique environment. An eighth-generation Floridian, Ward has always had an interest

, Democratic Republic of Congo (DRC, hereafter) and Gabon, are responsible for seventy-seven percent adequately protected. Three countries (Gabon, Equatorial Guinea, and Guinea Bissau) do not have national park

Sample records for gabon mauritania niger from the National Library of Energy Beta (NLEBeta)

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between East (Kenya and Zimbabwe) and West/Central sub-Saharan (Gabon) African populations. A skew toward heterogeneity in levels of polymorphism and divergence in the Gabon sample suggest that this population

to the CamarounÂ­Gabon border, whence south to the Cape chrysippus is the only form. Even collections from the islands of Fernando Po (off Camaroun) and Sao~ ThomeÂ´ (west of Gabon) are also monomorphic for alcippus

This paper describes the mineralogy of a phyllosilicate/uraninite/galena-bearing vein located within the hydrothermal alteration halo associated with the Bangombe reactor. Phyllosilicates within the vein include a trioctahedral Al-Mg-Fe chlorite (ripidolite), Al-rich clay (kaolinite and/or donbassite) and illite. Textural relations obtained by backscattered-electron imaging suggest that ripidolite crystallized first among the sheet silicates. Uraninite is spatially associated with ripidolite and probably precipitated at a later time. While energy-dispersive X-ray analyses suggest that the uranium phase is predominantly uraninite, coffinite or other phases may also be present.

Airborne transient electromagnetic (TEM) is a cost-effective method to image the distribution of electrical conductivity in the ground. We consider layered earth inversion to interpret large data sets of hundreds of kilometre. Different strategies can be used to solve this inverse problem. This consists in managing the a priori information to avoid the mathematical instability and provide the most plausible model of conductivity in depth. In order to obtain fast and realistic inversion program, we tested three kinds of regularization: two are based on standard Tikhonov procedure which consist in minimizing not only the data misfit function but a balanced optimization function with additional terms constraining the lateral and the vertical smoothness of the conductivity; another kind of regularization is based on reducing the condition number of the kernel by changing the layout of layers before minimizing the data misfit function. Finally, in order to get a more realistic distribution of conductivity, notably...

A recently discovered species flock of mormyrid fishes is marked by a striking degree of electric signal diversity among species of rather similar form. We investigated electric organ discharge (EOD) variation...

Malaria remains one of the most important infectious diseases in pregnancy in sub-Saharan Africa. Whereas seasonal malaria chemoprevention is advocated as public health intervention for children in certain areas ...

Postrelease monitoring is an important aspect of reintroduction projects, one outcome of which is to allow an assessment of the initial success of the reintroduction, often measured by quantifying survival and...

Each of the pathogenic human retroviruses (HIV-1/2 and HTLV-1) has a non-human primate (NHP) counterpart, and the presence of these retroviruses in humans results from interspecies transmission. The passage of an...

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.mapress.com/zootaxa/ A new species of African Forest Robin from Gabon (Passeriformes: Muscicapidae: Stiphrornis) BRIAN K@si.edu Abstract We describe a new species of forest robin from the Gamba Complex in southwest Gabon. This common- cally diverse Gamba Complex of Protected Areas in Gabon, is a primary conservation priority. In 2000

National Park in Gabon on the equatorial West African coast. The National Park includes critical nesting, fisheries, Gabon, leatherback turtle, marine protected area, nesting. The use of marine protected areas). Leatherback turtles nesting in Gabon (Fig. 1a) form a globally important sub-population (Fretey, 1984; Formia

, Franceville, Gabon During the period of December 2004 to January 2005, Bacillus anthracis killed three wild has had a devastating effect on the Central African great ape populations of Gabon and the Republic 1994 and 1996 throughout Minkebe Forest, which is located in northeastern Gabon close to the border

Gabon, Congo and Angola, presents large depocenters where sediments have been accumulating since Early is shifted northward and reaches the CongoÂ­Gabon boundary on the shelf. Sedimentation on the slope directed long- shore drifts that build extensive sand bars along the Congo and Gabon shoreline. The low

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10.1007/s10393-010-0364-4 High Prevalence of the Amphibian Chytrid Pathogen in Gabon Rayna C. Bell of the Amphibian Chytrid Pathogen in Gabon Rayna C. Bell,1 Adriana V. Gata Garcia,1 Bryan L. Stuart,2 and Kelly R two national parks in Gabon (Monts de Cristal and Ivindo). Bd was detected in 20 of the 42 species

) from a riverine species flock in Gabon, Central Africa Matthew E. Arnegard & Carl D. Hopkins Department the rivers and streams of Gabon. Introduction Numerous mate attraction signals playing a role in species in an undescribed Brienomyrus species from Gabon. A neural pathway for EOD temporal coding was subsequently

.mapress.com/zootaxa/ A new Stomatorhinus (Osteoglossomorpha: Mormyridae) from the Ivindo River, Gabon, West Central Africa River, in Gabon, West Central Africa. This species is characterized by its very small size which with visible tubes and pores. Stomatorhinus ivin- doensis is endemic to the Ivindo River basin of Gabon

in extensional regions. Like many margins, the edge effect `high' offshore Gabon. West Africa is located at the shelf break in the region of maximum sediment thickness. Gabon differs, however, from other margins along-strike of the Gabon margin and that passive margins may be highly segmented as regards their long

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(Ott 1993). I compared changes in mean distance between squirrels among areas using a Kruskal- Wallis test at P &0. 05 (Ott 1993). I also compared mean change in distance between July August Outobtx 14-15-16-17-18-19-20-21-22-23, 4-5-6-7-8-9-13-14.... Comparisons of home range sizes were made using the Kruskal-Wallis tests and Wilcoxon rank sum tests at P & 0. 05 (Ott 1993), and the SAS computer program (SAS Inc, 1995). 15 The mean coordinates (X, Y) for each squirrel were calculated using Calhome (Kie...

studies, it also attempted to shed some light on the effects of the ongoing gravity tectonics, and the region's unique littoral circulation pattern, on surface sedimentation in deep water. To achieve its goals this study employed select geotechnical tests...

starch strands apart thus increasing the hydrolyzable surface, or alternatively it may localize to the catalytic domain is attached is flexible, allowing the catalytic site to access a large surface area Cellulomonas fimi has two noncatalytic binding domains that clearly bind to different ligands; xylan binds only

...overestimation due to the adherence of phosphate particles to the mycelium (19). Uninoculated...supplemented with 3 g of rock phosphate (particle size 75 mum in diameter) per liter...extracellular enzyme glucose oxidase (GOD), which converts glucose into gluconic...

This paper describes the first use of Hydrology-Entomology and Malaria Transmission Simulator (HYDREMATS), a physically based distributed hydrology model, to investigate environmental management methods for malaria vector ...

XIV. Morocco (Including Western Sahara and Mauritania) EIA/ARI World Shale Gas and Shale Oil Resource Assessment XIV. Morocco (Including Western Sahara and Mauritania) EIA/ARI World Shale Gas and Shale Oil Resource Assessment May 17, 2013 XIV-1 XIV. MOROCCO (INCLUDING WESTERN SAHARA AND MAURITANIA) SUMMARY In addition to large accumulations of Late-Cretaceous immature oil shale (kerogen) at depths suitable for surface mining 1 , Morocco and its two neighboring countries, Mauritania and Western Sahara, also possess organic-rich Silurian- and Devonian-age shale gas and shale oil potential in the Tindouf and Tadla basins, Figure XIV-1. Mapping and resource characterization of these shales is challenging because regional deformation, erosion and subsidence of the shale deposits have led to their discontinuous and complex present day distribution. Figure XIV-1. Shale Gas Basins of Morocco, Western Sahara and Mauritania

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and irrigation are obvious ways that agriculturalists alter plant microclimate. Reducing excessive wind provides another way to ameliorate crop environment. It is difficult to determine when windbreaks were first used in agricultural systems but it is likely... of the microclimatic study indicate that wind speed, relative humidity, daily minimum air temperature and pan evaporation were all significantly altered in the protected field. Daily maximum and average air temperatures were not affected. The results...

Mean maximum start-up accelerations and velocities achieved by the fast-start specialist, northern pike, are reported at 120 ms-2 and 4 ms-1, respectively (Harper and Blake, 1990). In this thesis, a simple mechanical system ...

The Douala Basin is a stable Atlantic-type, predominantly offshore basin and forms the northern terminal of a series of divergent passive margin basins located on the Southwest coast of Africa that resulted from the rifting of Africa from South America. An integration of new studies including detailed well, biostratigraphic, sedimentological, geochemical and seismic data has confirmed that the tectonostratigraphic evolution in the basin can be broadly divided into three developmental phases: the Syn-rift, Transitional and Drift phases. This basis has been explored intermittently for hydrocarbon for the past 40 years with two important gas fields discovered and no commercial oil found as yet. This early gas discovery and a corresponding lack of any significant oil discovery, led early operators to term this basin as essentially a gas province. However, recent geochemical analyses of various oil-seeps and oil samples from various localities in the basin, using state-of-the-art techniques have demonstrated that this basin is a potential oil prone basin. The results show that two models of oil sourcing are possible: a Lower Cretaceous lacustrine saline source, similar to the presalt basins of Gabon or a marine Upper Cretaceous to lower Tertiary source, similar to the neighbouring Rio del Rey/Niger Delta Complex. Additionally, seismic reflection data also demonstrate a variety of reservoir horizons, including submarine fans, channel-like features and buried paleohighs, all interbedded within regionally extensive, uniformity bounded mudstone units. Hence, it is now quite evident that within this basin, there exist a vast potential for a wide variety of stratigraphic, structural and combined traps. These features, which are considered to have significantly enhanced the prospectivity of this basin, will be discussed in this paper.

...Ngounie rivers as main tributaries. At the city of Lambarene, where the river enters...mum and the laser was operated using an energy density of 15J/cm2 at a frequency of...proportion of a younger component. These independant sets of data support the views that recent...

fishing pressure. Key marine biodiversity includes major fishing resources and globally important marine been co-ordinating a UK government funded, Darwin Initiative project for marine biodiversity of Gabon actions needed for the conservation of marine biodiversity in Gabon under the five strategies suggested

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Field studies have demonstrated that several species of mormyrid fish from Gabon, West Africa have a sex difference in the pulse-like waveform of their Electric Organ Discharge (EOD). Administration of androgen h...

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in several Norwegian fjords with water depths of 200 m, phytoplankton ... 1998) and has attracted considerable mathematical treatment. (Shigesada and ... distribution (cells per unit volume) but also of the total pop- ulation size per ... constant of integration equals zero, we get the slope of the ... Ocean offshore Mauritania).

Energy consumption and carbon dioxide emissions from 16 oil-exporting countries are studied using Data Envelopment Analysis using indicators representing economic growth, energy consumption and emissions. The analysis for 1996 shows that Norway, Gabon and Nigeria are efficient and that Russia is inefficient. Malmquist Productivity Index analysis shows that there is progress in achieving higher values of GDP and non-fossil fuel consumption and in achieving lower values of fossil fuel consumption and carbon emissions in the year 1996 when compared with 1992 for Norway, Russia, Mexico, Algeria, Libya, Gabon and Oman.

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......boundaries are not isochrons. Oil industry and academic data have...South Atlantic FZs south of the Marathon and Mercurius FZs, which misfitting...basins of Gabon-geology and oil systems, in Divergent/passive...Gateway (ODP Leg 159), in The oil and gas habitats of the South......

......modification of the standard model of electroweak...109 yr ago in Oklo Uranium Mine in Gabon...also see the recent review by Garcia-Berro...communication, we plan to address each...propagates along standard null geodesics...distance computed in a standard fashion in the context......

that are morphologically cryptic in sympatry but produce alternate types of electric organ discharge (EOD). Other species in a large group containing a clade of these morphologically cryptic EOD types produce stereotyped, species-typical EOD waveforms thought to function in mate recognition. First, for six populations from Gabon

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This article discusses how Africa's large producers are offering incentives to attract exploration. Egypt is pushing new gas development, while Nigeria announced reduced taxes to lure foreign operators. Gabon has rejuvenated its production with discovery of a large new oil field. Libya is offering liberal concession terms, though the status of U.S. firms is uncertain.

The author reviews the oil market in Africa. Some of the highlights are: Nigeria restructures NNPC to make it competitive, offers new terms; Libya redraws its concession terms in hopes of attracting more operators; New onshore finds may keep Gabon from becoming a producer in decline; and South Arica has struck what may be commercial oil south of Mossel Bay.

An analysis of the Oklo natural reactor, a self-sustaining and self-regulating critical assembly that existed some 2 billion years ago in Gabon, Africa, is presented. Nonlinear continuous dif ferential and nonlinear discrete iterative formulations are established and selected parameter characterizations identified. Conceivable power oscillations are calculated and discussed. Some implications of nonlinear mappings for nuclear simulation are suggested.

......material from a large rising thermal anomaly beneath southern Ethiopia...Central Africa from Angola to Sudan. In the Archaean, the Gabon-Cameroon...attributed to convection driven by thermal gradients between the asthenosphere...upper-mantle LPO due to the thermal gradient at the edge of the......

Â· Borneo Â· Congo Basin1 Â· Mekong Region2 Â· Southern Chile. The project also assesses the role of China Report 1 The Congo Basin includes the nations of Cameroon, the Central African Republic, the Democratic Republic of the Congo, Equatorial Guinea, Gabon and the Republic of the Congo. 2 The Mekong Region includes

Although there has been a decrease in oil prices, activity along coastal West Africa has tended to increase, with emphasis on field development and production. Because of a world-wide surplus of petroleum, Nigeria has had to cut production by more than half and offshore operations have been affected also. Off the coast of Gabon exploration activity has increased with numerous wildcat rigs which are potentially highly productive. Overall production in Gabon has decreased slightly since 1980. The People's Republic of the Congo, on the other hand, has increased productivity due to new successful fields, while in the Angola/Cabinda area new offshore programs are forming. Production and exploration increases are also expected for Ghana, Zaire, Cameroon, and South Africa. (JBF)

Oil industry activity in central and southern Africa appears to have stabilized in the last few years, but some activities (such as field development and exploration acreage acquisition) are still declining. Several countries have advertised open concessions and invited bids. Only in a very few cases have the offers stimulated the interest of oil companies. An exceptional increase in exploration concession acquisition took place in the East Africa rift area. Land seismic acquisition increased mostly in Nigeria, but 1985 marine seismic activity was half the 1984 activity. Exploration drilling was higher than in 1984, but development drilling was considerably lower. Significant discoveries were made in Gabon and Angola. Production increased 8%, with the largest and most significant increase in Angola, followed by Gabon. The production share of non-OPEC versus OPEC countries remained stable at 33%. 33 figures, 6 tables.

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Some writers have presented possible scenarios in which a subcritical underground deposit of plutonium or other fissile material might be changed into a critical configuration. The underground criticalities that occurred in Gabon some 1.7 billion years ago in deposits of natural uranium is cited. Other scientists assert that it is virtually impossible that such a configuration could develop in an underground repository. The author presents the pros and cons of these views. 5 refs.

This book reviews the tectonic setting, basin development and history of exploration of a number of selected petroleum provinces located in a variety of settings in the Middle East, North Sea, Nigeria, the Rocky Mountains, Gabon and China. This book illustrates how ideas and models developed in one area may be applied to other regions. Regional reviews and the reassessment of petroleum provinces are presented.

According to the author, the first sustained nuclear fission chain reaction was not at the University of Chicago, but at the Oklo site in the African country of Gabon. Proof of this phenomenon is provided by mass spectrometric and analytical chemical measurements by French scientists. The U.S. experience in developing power-producing reactors and their related fuel and fuel cycles is discussed.

Fewer wells and less footage were drilled in 1986 compared to 1985. Total drilling decreased by 23% as 217 wells were completed compared to 289 in 1985. Footage drilled during 1986 declined by 52%; about 1.3 million ft were drilled compared to about 2.7 million feet in 1985. The success rate for exploration wells of 34% during 1986 is due to considerably higher success rates in Nigeria and Gabon compared to 1985. Significant discoveries were made in Nigeria, Angola, Congo, and Gabon. Seismic acquisition was the major geophysical activity during 1986. Seismic activity (2-D and 3-D) decreased by 12% to about 230 crew-months. Total 2-D seismic kilometers recorded increased by 26% to about 82,000 km due to significant 2-D marine seismic activity in Nigeria and Angola. Surface geology, photogeology, geochemistry, gravimetry, and aeromagnetic surveys decreased compared to 1985. Total oil production in 1986 was 834 million bbl (about 2.2 million BOPD), an increase of 2%, with the most significant increased in Cameroon and Angola. The production share of OPEC countries (Nigeria and Gabon) versus non-OPEC countries increased to 72% in 1986 compared to 67% in 1985. 32 figures, 5 tables.

prospecting for oil and gas in the basin. Abstracts on Niger Delta studies abound in the literature, but only and Geophysics, University of Missouri-Rolla, Rolla, MO 65409, USA b Department of Geology, University of Nigeria

: to investigate, describe and analyse Christian theological and socio-political consciousness within the context of oil and conflict in the Niger Delta region of Nigeria from Baptist and Pentecostal perspectives; and to use the data to test the veracity...

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The Aptian Salt basin of west Africa, extends from Equatorial Guinea southward to Angola, contains recoverable reserves estimated at nearly 4 billion BOE, and is current producing 600,000 BOPD. The basin developed as a result of tensional forces between west Africa and South America initiated at the end of the Jurassic. The prospective sedimentary sequences ranged in age from Early Cretaceous (uppermost Jurassic in places) to Holocene and is divided by the Aptian transgressive sand and salt into a pre-salt, nonmarine, syn-rift sequence and a post-salt, marine, post-rift sequence. Both the pre- and post-salt sequences contain several successful exploration plays, the most prolific of which are the Early Cretaceous nonmarine sandstone fields in tilted fault blocks of Gabon and Cabinda; Early Cretaceous carbonate buildups on the margins of basement highs in Cabinda; Early Cretaceous transgressive marine sandstone fields in anticlines draped over basement highs in Gabon; Late Cretaceous shallow marine sandstone and carbonate fields in salt-related structures in the Congo, Zaire, Cabinda, and Angola; Late Cretaceous dolomites in structural/stratigraphic traps in Angola; Late Cretaceous/early Tertiary deltaic/estuarine sandstone traps formed by salt movement in Gabon, Cabinda, and angola; and Tertiary marine turbidite fields in Cabinda and Angola. Despite the exploration success in these trends, much of the basin is under or poorly explored. The major problems for exploration are the poor quality of seismic definition beneath the salt, which makes it difficult to predict pre-salt structure and stratigraphy, and the importance of a stratigraphic element in many of the post-salt traps, also difficult to detect on seismic.

Early Cretaceous rift basins of northeastern Brazil illustrate key three-dimensional geometries of intracontinental rift systems, controlled mainly by the basement structures. These basins were formed and then abandoned during the early extension associated with the north-south-propagating separation of South America and Africa. During the early Neocomian, extensional deformation jumped from the easternmost basins (group 1: Sergipe Alagoas and Gabon basins; group 2: Reconcavo, Tucano, and Jatoba basins) to the west, forming a series of northeast-trending intracratonic basins (group 3: Araripe, Rio do Peixe, Iguatu, Malhada Vermelha, Lima Campos, and Potiguar basins). The intracratonic basins of groups 2 and 3 consist of asymmetric half-grabens separated by basement highs, transfer faults, and/or accommodation zones. These basins are typically a few tens of kilometers wide and trend northeast-southwest, roughly perpendicular to the main extension direction during the early Neocomian. Preexisting upper crustal weakness zones, like the dominantly northeast-southwest-trending shear zones of the Brazilian orogeny, controlled the development of intracrustal listric normal faults. Internal transverse structures such as transfer faults (Reconcavo basin and onshore Potiguar basin) and accommodation zones (onshore Potiguar basin and Araripe basin) were also controlled by the local basement structural framework. Transverse megafaults and lithostructural associations controlled the three main rift trends. The megashear zones of Pernanbuco (Brazil)-Ngaundere (Africa) apparently behaved like a huge accommodation zone, balancing extensional deformation along the Reconcavo-Jatoba/Sergipe Alagoas-Gabon trends with simultaneous extension along the Araripe-Potiguar trend. The Sergipe Alagoas-Gabon trend and the Potiguar basin represent the site of continued evolution into a marginal open basin following early Neocomian deformation.

The study of lead, ruthenium, and technetium transport in nature requires the mass spectrometric analyses of large numbers of geologic samples. This quarter about 200 samples arrived from Gabon, which were collected at the Oklo mine in September. Work was performed to improve the lead and ruthenium chemical procedures and the mass spectrometric instrumentation in preparation for analyzing many of the Oklo samples and a large number of the 402 samples on hand from Key Lake, Canada. Data concerning ruthenium isotopic alterations from samples near an Oklo natural fission reactor zone indicated that ruthenium or technetium were not transported to distances greater than the 10 meters detected previously.

Obtaining capital is a critical element in the production expansion plans of OPEC member countries. Another issue that may impact the plans is the environmental taxes that may reduce the call on OPEC oil by 5 million b/d in 2000 and about 16 million b/d in the year 2010. This concluding part of a two-part series discusses the expansion possibilities of non-Middle East OPEC members, OPEC's capital requirements, and environmental concerns. Non-Middle East OPEC includes Algeria, Gabon, Indonesia, Libya, Nigeria, and Venezuela.

This paper summarizes the drilling and exploration activity of the oil and gas industries of Egypt, Libya, Tunisia, Algeria, Morocco, Nigeria, Cameroon, Gabon, the Congo, Angola, and South Africa. Information is provided on current and predicted trends in well drilling activities (both onshore and offshore), numbers of new wells, footage information, production statistics and what fields accounted for this production, and planned new exploration activities. The paper also describes the current status of government policies and political problems affecting the oil and gas industry.

A review of corrosion problems on the 670-mile land and offshore system operated by Elf Gabon indicated that internal corrosion has been the most persistent problem. The company has operated the system since 1959. Causes include the presence of CO{sub 2} in polyphasic lines, residual oxygen and sulfate-reducing bacteria SRBP in water-injection lines, and bacterial corrosion in crude-oil lines. External corrosion has been less troublesome, caused either by atmospheric marine exposure with frequent wetting or by disbonded coatings on buried pipes.

Offshore studies have been completed in the Gulf of Guinea, off West Africa. An area has been selected over the Gabon continental slope. A morpho-sedimentological zonation is made regarding acoustic data and geotechnical characteristics of sampled sediments. An old slide has been considered as a criteria for estimating realistic slope failure conditions. Both drained and undrained formulations tend to prove that fluid escape is the most realistic explanation for slides occurrence. Regional hazard charts also allow them to present unstable zones and build up criteria for structures implantation.

Internal corrosion has proved the most persistent corrosion problem on the approximately 670 miles of pipelines operated since 1959 by Elf Gabon. Causes include the presence of CO{sub 2} in polyphasic lines, residual oxygen and sulfate-reducing bacteria (SRB) in water-injection lines, and bacterial corrosion in crude-oil lines. External corrosion has been less troublesome, caused either by atmospheric marine exposure with frequent wetting or by disbonded coatings on buried lines. These were the major conclusions of a review conducted by the company and presented here in two parts. This article focuses on external corrosion.

This paper describes slim hole bit design developed at the Paris School of Mines and Security DBS. The design is a compromise between several criteria such as drilling efficiency, uniform wear distribution around the bit face and low level of vibration of the bit, according to the hole diameter and the formation characteristics. Two new bits were manufactured and run successfully in a full scale drilling test bench and in field test in Gabon. The result show improvement of the drilling performances in slimhole application.

This article is a survey of the drilling activity and petroleum activity in Africa. The areas which seem to hold the highest promise for new discoveries or increased exports are Egypt's Western Desert which seems to offer the possibility of significant oil discoveries. In addition, Nigeria has dramatically increased its exploration activity which is counter to the global trend in 1986. Areas where activity is decreasing are Cameroon, South Africa. It is pointed out that the Gabon crude oil reserves may have been raised 60% by a single on-shore discovery.

3, 2011 3, 2011 Same Fungus, Different Strains: A Comparative Genomics Approach for Improved "Green" Chemical Production WALNUT CREEK, Calif.-Fungi play key roles in nature and are valued for their great importance in industry. Consider citric acid, a key additive in several foods and pharmaceuticals produced on a large-scale basis for decades with the help of the filamentous fungus Aspergillus niger. While A. niger is an integral player in the carbon cycle, it possesses an arsenal of enzymes that can be deployed in breaking down plant cell walls to free up sugars that can then be fermented and distilled into biofuel, a process being optimized by U.S. Department of Energy researchers. Susannah Tringe Photo: Aspergillus niger conidiospore by Kathie T. Hodges, Cornell.

1 Volume 8 Issue 3 1 Volume 8 Issue 3 For decades, citric acid has been produced on a commercial- scale basis with the help of the fungus Aspergillus niger. Outside industry, A. niger is also known to be involved in the global carbon cycle, and its enzymes can be used to break down plant cell walls and get at the sugars that can in turn be fermented for use as biofuels. "Aspergillus niger is an industrial workhorse for enzymes and small molecules such as organic acids," said Scott Baker of the Pacific Northwest National Laboratory. "We know that this single organism is used for production of organic acids and for enzymes, and it can degrade plant cell wall matter for sugar production. For biofuels it's a highly relevant organism since it's already been

The Douala basin is predominantly an offshore basin extending from the Cameroon volcanic line in the north to the Corisco arch in the south near the Equatorial Guinea-Gabon border. The basin lies wholly within the territorial borders of Cameroon and Equatorial Guinea. The Douala basin is one of a series of divergent margin basins occurring along the southwest African coastline resulting from the rifting of Africa from South America. Continental rifting in the Doula basin was initiated at least by Aptian-Albian time and possibly as early as Jurassic. The rift stage persisted until Albian time when the onset of drifting occurred. The sedimentary section in the basin has a maximum thickness of 8-10 km, based on exploration drilling and gravity and magnetics modeling. The synrift section consists of Aptian-Albian sands and shales, deposited primarily as submarine fans, fan-deltas, and turbidite deposits. These are overlain by salt, thought to be equivalent to the Ezagna salt of Aptian age in the Gabon basin to the south. The synrift section is separated from the overlying postrift shale sequence of Late Cretaceous and Tertiary age by a major late Albian unconformity. The Douala basin has been explored for hydrocarbons intermittently over the last 25 years. Results show a distinct tendency for gas-proneness. The largest field recorded to date is the Sanaga Sud gas field, discovered in 1979, offshore, near the coastal city of Kribi.

. An oil spill occurred in January of 1998, the slick drifted in the opposite direction at twice the speed as was anticipated. It was believed that the heavy discharge from the Niger River Delta would have a strong influence on the near-shore circulation...

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......masked out and the conservation of the total water mass has been enforced...control the amount of water that produces gravity variations (Pool Eychaner 1995...semi-arid Niger. Water Resour. Res...wrcr.20235. Pool D.R. , Eychaner......

...these classifications do not imply fundamental differences in the mechanisms that control...the assistance of Stalins regime, to force others to accept his views had disastrous...1986). Hyoscyamus niger. In CRC Handbook of Flowering, Vol. V, A.H. Halevy...

...Niger, Ivory Coast, and Sudan) that are not producers at...account recent higher costs of thermal generation, or the potential...hydroelectricity, is one-third geo-thermal (22). Significant biomass...changes. In the industrial, thermal electric, and residential...

Bilateral Partnerships Bilateral Partnerships NREL partners with more than 50 countries around the world to advance development and use of renewable energy and energy efficiency technologies: Angola Argentina Australia Bangladesh Brazil Canada Chile China Colombia Costa Rica Gabon Haiti India Indonesia Japan Kazakhstan Kenya Korea Mexico North America Philippines Saudi Arabia U.S. Pacific Territories United Arab Emirates Vietnam Asia Bangladesh Under sponsorship from the U.S. Agency for International Development (USAID), NREL provides technical support for mapping the wind resource in the Bay of Bengal littoral zone in order to provide sufficiently accurate information for national-level strategic energy planning. China NREL manages renewable energy cooperation with China under the U.S.-China

Comprises the sum of Africa, North America, South America, Asia, Europe, Comprises the sum of Africa, North America, South America, Asia, Europe, Oceania, the former U.S.S.R., and the Antarctic Fisheries. 2 Includes Christmas Island. 3 Identifies bunkers delivered by tankers to vessels on the Antarctic fishing grounds; fuels delivered to Antarctic research stations are not included. 4 Refers to former Burma. 5 Refers to the former Democratic Kampuchea. 6 Excludes Taiwan province. 7 Includes Taiwan Province. 8 Prior to 1 January 1993, refers to the former Czechoslovakia composed of the Czech Republic and Slovakia. 9 Code used for population data only. Energy statistics for France and Monaco are combined (251). 10 From 1950 to 1958, data includes the Central African Republic, Chad, Congo, and Gabon. 11 From 1950 to 1954, data includes Cambodia, Laos, and Vietnam.

Nearly 200 samples were collected at the Oklo mine in Gabon this quarter for shipment to the United States to continue studies of lead, ruthenium, and technetium migration around natural fission reactors. The first analyses of samples collected near a rich uranium ore body in Canada show the presence of radiogenic lead in pyrite and sandstone materials. Analyses of additional samples are underway to permit the interpretation of the data in terms of transport paths. A technique was developed this quarter to eliminate the interference of organic materials during the mass spectrometric analyses of ruthenium in Oklo samples with high asphaltic contents. A proposal was drafted for a study of naturally occurring radionuclide migration at rich uranium ore bodies in Australia to be performed jointly by the US Department of Energy and the Australian Atomic Energy Commission.

At its experimental submarine station in the Grondin field offshore the West African state of Gabon, Societe Nationale Elf-Aquitaine has run a series of inspection, repair, and maintenance tests on two producing wells using a robot controlled from the surface. Designed for water depths beyond the range of divers, the TIM robot has a pair of manipulator arms and a rotating telescopic crane installed on a 14 by 7.6 ft carriage. Five television cameras fitted at various spots on the robot allow surface operators to direct TIM in such tasks as (1) installing a jumper pipe between a Christmas tree and the manifold, (2) connecting a jumper electric cable and hydraulic hose, (3) locally operating a safety valve, and (4) removing a guide line. During 104 hr of seabed experience, TIM outperformed divers, particularly in jobs requiring great strength.

A significant portion of the LPG fraction of the associated gas from a small field can be economically recovered even in remote locations. An example is the Breme field, for which Elf Gabon is the operator. Situated 50 miles from Port Gentil, the field is located on a narrow strip of land between the sea and a lagoon, with access only by plane or boat. A prefabricated, skid-mounted, turnkey plant is now efficiently recovering gas condensate from the field flare. At the full rated 14 MMscfd gas flow (55 psia), the recovered LPG can add as much as 650 b/d to the 12,000 b/d crude oil production rate, 6 vol %. The plant includes a compact plate heat exchanger and a rotating thermal separator (RTS) that requires little maintenance, minimal control, and no outside energy.